body {
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    background-color: black;
    /*格式化背景*/
}

.stream-light-btn {
    width: 400px;
    /*设置好宽高*/
    height: 100px;
    padding: 5px 10px;
    text-decoration: none;
    line-height: 100px;
    text-align: center;
    text-transform: uppercase;
    font-size: 24px;
    color: #fff;
    /*结合css3样式定位居中*/
    background-image: linear-gradient( 135deg, #F6D242 10%, #FF52E5 100%);
    /*设置背景颜色渐变*/
    background-size: 400%;
    /*设置背景填充比例,放大4倍,使颜色过渡柔和,淡化线条*/
    border-radius: 50px;
    position: relative;
    z-index: 1;
}

.stream-light-btn::before {
    content: "";
    position: absolute;
    top: -5px;
    left: -5px;
    right: -5px;
    bottom: -5px;
    background-image: linear-gradient( 135deg, #F6D242 10%, #FF52E5 100%);
    /*设置背景颜色渐变*/
    background-size: 400%;
    border-radius: 50px;
    z-index: -1;
}

.stream-light-btn:hover {
    animation: stream 6s infinite linear;
    /*开启动画帧,线性移动背景,无限循环*/
}

.stream-light-btn::before:hover {
    animation: stream 6s infinite linear;
    /*开启动画帧,线性移动背景,无限循环*/
}

@keyframes stream {
    100% {
        background-position: -400% 0;
    }
}